The Seljuq/Seljuk empire was founded by Tughril Beg (1016-1063) in 1037. Tughril was raised by his grandfather, Seljuk-Beg, who was in a high position in the Oghuz Yabgu State. Seljuk gave his name to both the Seljuk empire and the Seljuk dynasty. The Seljuqs united the fractured political scene of the eastern Islamic world and played a key role in the first and second crusades. Highly Persianized[10] in culture[11] and language,[12] the Seljuqs also played an important role in the development of the Turko-Persian tradition,[13] even exporting Persian culture to Anatolia.[14][15] The settlement of Turkic tribes in the northwestern peripheral parts of the empire, for the strategic military purpose of fending off invasions from neighboring states, led to the progressive Turkicization of those areas.[16]

The Seljuqs were allied with the PersianSamanid shahs against the Qarakhanids. The Samanid fell to the Qarakhanids in Transoxania (992–999), however, whereafter the Ghaznavids arose. The Seljuqs became involved in this power struggle in the region before establishing their own independent base.

Alp Arslan, the son of Chaghri Beg, expanded significantly upon Tughril's holdings by adding Armenia and Georgia in 1064 and invading the Byzantine Empire in 1068, from which he annexed almost all of Anatolia. Arslan's decisive victory at the Battle of Manzikert in 1071 effectively neutralized the Byzantine resistance to the Turkish invasion of Anatolia.[20] He authorized his Turkmen generals to carve their own principalities out of formerly Byzantine Anatolia, as atabegs loyal to him. Within two years the Turkmens had established control as far as the Aegean Sea under numerous beghliks (modern Turkish beyliks): the Saltukids in Northeastern Anatolia, Mengujekids in Eastern Anatolia, Artuqids in Southeastern Anatolia, Danishmendis in Central Anatolia, Rum Seljuqs (Beghlik of Suleyman, which later moved to Central Anatolia) in Western Anatolia, and the Beylik of Tzachas of Smyrna in İzmir (Smyrna).

Under Alp Arslan's successor, Malik Shah, and his two Persian viziers,[21]Nizām al-Mulk and Tāj al-Mulk, the Seljuq state expanded in various directions, to the former Iranian border of the days before the Arab invasion, so that it soon bordered China in the east and the Byzantines in the west. Malikshāh moved the capital from Rey to Isfahan. The Iqta military system and the Nizāmīyyah University at Baghdad were established by Nizām al-Mulk, and the reign of Malikshāh was reckoned the golden age of "Great Seljuq". The Abbasid Caliph titled him "The Sultan of the East and West" in 1087. The Assassins (Hashshashin) of Hassan-i Sabāh started to become a force during his era, however, and they assassinated many leading figures in his administration; according to many sources these victims included Nizām al-Mulk.

The Seljuq power was at its zenith under Malikshāh I, and both the Qarakhanids and Ghaznavids had to acknowledge the overlordship of the Seljuqs.[22] The Seljuq dominion was established over the ancient Sasanian domains, in Iran and Iraq, and included Anatolia as well as parts of Central Asia and modern Afghanistan.[22] The Seljuk rule was modelled after the tribal organization common in Turkic and Mongol nomads and resembled a 'family federation' or 'appanage state'.[22] Under this organization, the leading member of the paramount family assigned family members portions of his domains as autonomous appanages.[22]

When Malikshāh I died in 1092, the empire split as his brother and four sons quarrelled over the apportioning of the empire among themselves. Malikshāh I was succeeded in Anatolia by Kilij Arslan I, who founded the Sultanate of Rum, and in Syria by his brother Tutush I. In Persia he was succeeded by his son Mahmud I, whose reign was contested by his other three brothers Barkiyaruq in Iraq, Muhammad I in Baghdad, and Ahmad Sanjar in Khorasan. When Tutush I died, his sons Radwan and Duqaq inherited Aleppo and Damascus respectively and contested with each other as well, further dividing Syria amongst emirs antagonistic towards each other.

In 1118, the third son Ahmad Sanjar took over the empire. His nephew, the son of Muhammad I, did not recognize his claim to the throne, and Mahmud II proclaimed himself Sultan and established a capital in Baghdad, until 1131 when he was finally officially deposed by Ahmad Sanjar.

During this time conflict with the Crusader states was also intermittent, and after the First Crusade increasingly independent atabegs would frequently ally with the Crusader states against other atabegs as they vied with each other for territory. At Mosul, Zengi succeeded Kerbogha as atabeg and successfully began the process of consolidating the atabegs of Syria. In 1144 Zengi captured Edessa, as the County of Edessa had allied itself with the Ortoqids against him. This event triggered the launch of the Second Crusade. Nur ad-Din, one of Zengi's sons who succeeded him as atabeg of Aleppo, created an alliance in the region to oppose the Second Crusade, which landed in 1147.

Ahmad Sanjar had to contend with the revolts of Qarakhanids in Transoxiana, Ghorids in Afghanistan and Qarluks in modern Kyrghyzstan, as well as the nomadic Kara-Khitais who invaded the East and captured the Eastern Qarakhanid state. The Kara-Khitais then defeated the Western Qarakhanids, a vassal of the Seljuqs at Khujand. The Qarakhanids turned to their overlord the Seljuqs for help, but at the Battle of Qatwan in 1141, Sanjar was decisively defeated. The Seljuq army suffered great losses and Sanjar barely escaped with his life. The prestige of the Seljuqs became greatly diminished, and they lost all his eastern provinces up to the Syr Darya, with the vassalage of Western Kara-Khanid taken by the Kara-Khitan.[23]

In 1153, the Ghuzz (Oghuz Turks) rebelled and captured Sanjar. He managed to escape after three years but died a year later. Despite several attempts to reunite the Seljuks by his successors, the Crusades prevented them from regaining their former empire.[citation needed] The atabegs, such as Zengids and Artuqids, were only nominally under the Seljuk Sultan, and generally controlled Syria independently. When Ahmed Sanjar died in 1156, it fractured the empire even further and rendered the atabegs effectively independent.

After the Second Crusade, Nur ad-Din's general Shirkuh, who had established himself in Egypt on Fatimid land, was succeeded by Saladin. In time, Saladin rebelled against Nur ad-Din, and, upon his death, Saladin married his widow and captured most of Syria and created the Ayyubid dynasty.

For a brief period, Togrul III was the Sultan of all Seljuq except for Anatolia. In 1194, however, Togrul was defeated by Takash, the Shah of Khwarezmid Empire, and the Seljuq finally collapsed. Of the former Seljuq Empire, only the Sultanate of Rûm in Anatolia remained. As the dynasty declined in the middle of the thirteenth century, the Mongols invaded Anatolia in the 1260s and divided it into small emirates called the Anatolian beyliks. Eventually one of these, the Ottoman, would rise to power and conquer the rest.

The Seljuqs were educated in the service of Muslim courts as slaves or mercenaries. The dynasty brought revival, energy, and reunion to the Islamic civilization hitherto dominated by Arabs and Persians. According to the Seljuqs, they brought to the Muslims "fighting spirit and fanatical aggression".[24]

The Seljuqs founded universities[25] and were also patrons of art and literature. Their reign is characterized by Persian astronomers such as Omar Khayyám, and the Persian philosopher al-Ghazali. Under the Seljuqs, New Persian became the language for historical recording, while Arabic language culture shifted from Baghdad to Cairo.[26]

^ abcC.E. Bosworth, "Turkish Expansion towards the west" in UNESCO History of Humanity, Volume IV, titled "From the Seventh to the Sixteenth Century", UNESCO Publishing / Routledge, p. 391: "While the Arabic language retained its primacy in such spheres as law, theology and science, the culture of the Seljuk court and secular literature within the sultanate became largely Persianized; this is seen in the early adoption of Persian epic names by the Seljuk rulers (Qubād, Kay Khusraw and so on) and in the use of Persian as a literary language (Turkish must have been essentially a vehicle for everyday speech at this time)."

^Concise encyclopedia of languages of the world, Ed. Keith Brown, Sarah Ogilvie, (Elsevier Ltd., 2009), 1110; "Oghuz Turkic is first represented by Old Anatolian Turkish which was a subordinate written medium until the end of the Seljuk rule."

^Grousset, Rene, The Empire of the Steppes, (New Brunswick: Rutgers University Press, 1988), 159, 161; "In 1194, Togrul III would succumb to the onslaught of the Khwarizmian Turks, who were destined at last to succeed the Seljuks to the empire of the Middle East."

"Aḥmad of Niǧde's al-Walad al-Shafīq and the Seljuk Past", A. C. S. Peacock, Anatolian Studies, Vol. 54, (2004), 97; "With the growth of Seljuk power in Rum, a more highly developed Muslim cultural life, based on the Persianate culture of the Great Seljuk court, was able to take root in Anatolia."

Meisami, Julie Scott, Persian Historiography to the End of the Twelfth Century, (Edinburgh University Press, 1999), 143; "Nizam al-Mulk also attempted to organise the Saljuq administration according to the Persianate Ghaznavid model..."

Encyclopaedia Iranica, "Šahrbānu", Online Edition: "... here one might bear in mind that non-Persian dynasties such as the Ghaznavids, Saljuqs and Ilkhanids were rapidly to adopt the Persian language and have their origins traced back to the ancient kings of Persia rather than to Turkmen heroes or Muslim saints ..."

Jonathan Dewald, Europe 1450 to 1789: Encyclopedia of the Early Modern World, Charles Scribner's Sons, 2004, p. 24: "Turcoman armies coming from the East had driven the Byzantines out of much of Asia Minor and established the Persianized sultanate of the Seljuks."

Grousset, Rene, The Empire of the Steppes, (Rutgers University Press, 1991), 161,164; "..renewed the Seljuk attempt to found a great Turko-Persian empire in eastern Iran..", "It is to be noted that the Seljuks, those Turkomans who became sultans of Persia, did not Turkify Persia-no doubt because they did not wish to do so. On the contrary, it was they who voluntarily became Persians and who, in the manner of the great old Sassanid kings, strove to protect the Iranian populations from the plundering of Ghuzz bands and save Iranian culture from the Turkoman menace."

Possessors and possessed: museums, archaeology, and the visualization of history in the late Ottoman Empire; By Wendy M. K. Shaw; Published by University of California Press, 2003, ISBN 0520233352, 9780520233355; p. 5.

Jackson, P. (2002). "Review: The History of the Seljuq Turkmens: The History of the Seljuq Turkmens". Journal of Islamic Studies (Oxford Centre for Islamic Studies) 13 (1): 75–76. doi:10.1093/jis/13.1.75.

Hancock, I. (2006). ON ROMANI ORIGINS AND IDENTITY. The Romani Archives and Documentation Center. The University of Texas at Austin.

Asimov, M. S., Bosworth, C. E. (eds.). (1998). History of Civilizations of Central Asia, Vol. IV: The Age of Achievement: AD 750 to the End of the Fifteenth Century, Part One: The Historical, Social and Economic Setting. Multiple History Series. Paris: UNESCO Publishing.

Encyclopaedia Iranica, "Šahrbānu", Online Edition: "... here one might bear in mind that non-Persian dynasties such as the Ghaznavids, Saljuqs and Ilkhanids were rapidly to adopt the Persian language and have their origins traced back to the ancient kings of Persia rather than to Turkmen heroes or Muslim saints ..."

Jonathan Dewald, "Europe 1450 to 1789: Encyclopedia of the Early Modern World", Charles Scribner's Sons, 2004, p. 24: "Turcoman armies coming from the East had driven the Byzantines out of much of Asia Minor and established the Persianized sultanate of the Seljuks."

C.E. Bosworth, "Turkmen Expansion towards the west" in UNESCO History of Humanity, Volume IV, titled "From the Seventh to the Sixteenth Century", UNESCO Publishing / Routledge, p. 391: "While the Arabic language retained its primacy in such spheres as law, theology and science, the culture of the Seljuk court and secular literature within the sultanate became largely Persianized; this is seen in the early adoption of Persian epic names by the Seljuk rulers (Qubād, Kay Khusraw and so on) and in the use of Persian as a literary language (Turkmen must have been essentially a vehicle for everyday speech at this time). The process of Persianization accelerated in the thirteenth century with the presence in Konya of two of the most distinguished refugees fleeing before the Mongols, Bahā' al-Dīn Walad and his son Mawlānā Jalāl al-Dīn Rūmī, whose Mathnawī, composed in Konya, constitutes one of the crowning glories of classical Persian literature."

Mehmed Fuad Köprülü, "Early Mystics in Turkish Literature", Translated by Gary Leiser and Robert Dankoff, Routledge, 2006, pg 149: "If we wish to sketch, in broad outline, the civilization created by the Seljuks of Anatolia, we must recognize that the local, i.e. non-Muslim, element was fairly insignificant compared to the Turkish and Arab-Persian elements, and that the Persian element was paramount. The Seljuk rulers, to be sure, who were in contact with not only Muslim Persian civilization, but also with the Arab civilizations in al-jazlra and Syria - indeed, with all Muslim peoples as far as India — also had connections with {various} Byzantine courts. Some of these rulers, like the great 'Ala' al-Dln Kai-Qubad I himself, who married Byzantine princesses and thus strengthened relations with their neighbors to the west, lived for many years in Byzantium and became very familiar with the customs and ceremonial at the Byzantine court. Still, this close contact with the ancient Greco-Roman and Christian traditions only resulted in their adoption of a policy of tolerance toward art, aesthetic life, painting, music, independent thought - in short, toward those things that were frowned upon by the narrow and piously ascetic views {of their subjects}. The contact of the common people with the Greeks and Armenians had basically the same result. {Before coming to Anatolia,} the Turkmens had been in contact with many nations and had long shown their ability to synthesize the artistic elements that thev had adopted from these nations. When they settled in Anatolia, they encountered peoples with whom they had not yet been in contact and immediately established relations with them as well. Ala al-Din Kai-Qubad I established ties with the Genoese and, especially, the Venetians at the ports of Sinop and Antalya, which belonged to him, and granted them commercial and legal concessions. Meanwhile, the Mongol invasion, which caused a great number of scholars and artisans to flee from Turkmenistan, Iran, and Khwarazm and settle within the Empire of the Seljuks of Anatolia, resulted in a reinforcing of Persian influence on the Anatolian Turks. Indeed, despite all claims to the contrary, there is no question that Persian influence was paramount among the Seljuks of Anatolia. This is clearly revealed by the fact that the sultans who ascended the throne after Ghiyath al-Din Kai-Khusraw I assumed titles taken from ancient Persian mythology, like Kai-Khusraw, Kai-Ka us, and Kai-Qubad; and that. Ala' al-Din Kai-Qubad I had some passages from the Shahname inscribed on the walls of Konya and Sivas. When we take into consideration domestic life in the Konya courts and the sincerity of the favor and attachment of the rulers to Persian poets and Persian literature, then this fact {i.e. the importance of Persian influence} is undeniable. With- regard to the private lives of the rulers, their amusements, and palace ceremonial, the most definite influence was also that of Iran, mixed with the early Turkish traditions, and not that of Byzantium."

Stephen P. Blake, Shahjahanabad: The Sovereign City in Mughal India, 1639-1739. Cambridge University Press, 1991. pg 123: "For the Seljuks and Il-Khanids in Iran it was the rulers rather than the conquered who were "Persianized and Islamicized"

Encyclopaedia Iranica, "Šahrbānu", Online Edition: "... here one might bear in mind that non-Persian dynasties such as the Ghaznavids, Saljuqs and Ilkhanids were rapidly to adopt the Persian language and have their origins traced back to the ancient kings of Persia rather than to Turkmen heroes or Muslim saints ..."

Encyclopaedia Britannica, "Seljuq", Online Edition: "... Because the Turkish Seljuqs had no Islamic tradition or strong literary heritage of their own, they adopted the cultural language of their Persian instructors in Islam. Literary Persian thus spread to the whole of Iran, and the Arabic language disappeared in that country except in works of religious scholarship ..."

F. Daftary, "Sectarian and National Movements in Iran, Khorasan, and Trasoxania during Umayyad and Early Abbasid Times", in History of Civilizations of Central Asia, Vol 4, pt. 1; edited by M.S. Asimov and C.E. Bosworth; UNESCO Publishing, Institute of Ismaili Studies: "... Not only did the inhabitants of Khurasan not succumb to the language of the nomadic invaders, but they imposed their own tongue on them. The region could even assimilate the Turkic Ghaznavids and Seljuks (eleventh and twelfth centuries), the Timurids (fourteenth–fifteenth centuries), and the Qajars (nineteenth–twentieth centuries) ..."

Professor Peter Golden has written one of the most comprehensive books on Turkic people, called An Introduction to the History of the Turkic Peoples (Peter B. Golden. Otto Harrasowitz, 1992). pg 386:

“Turkic penetration probably began in the Hunnic era and its aftermath. Steady pressure from Turkic nomads was typical of the Khazar era, although there are no unambiguous references to permanent settlements. These most certainly occurred with the arrival of the Oguz in the 11th century. The Turkicization of much of Azarbayjan, according to Soviet scholars, was completed largely during the Ilxanid period if not by late Seljuk times. Sumer, placing a slightly different emphasis on the data (more correct in my view), posts three periods which Turkicization took place: Seljuk, Mongol and Post-Mongol (Qara Qoyunlu, Aq Qoyunlu and Safavid). In the first two, Oguz Turkic tribes advanced or were driven to the western frontiers (Anatolia) and Northern Azarbaijan (Arran, the Mugan steppe). In the last period, the Turkic elements in Iran (derived from Oguz, with lesser admixture of Uygur, Qipchaq, Qaluq and other Turks brought to Iran during the Chinggisid era, as well as Turkicized Mongols) were joined now by Anatolian Turks migrating back to Iran. This marked the final stage of Turkicization. Although there is some evidence for the presence of Qipchaqs among the Turkic tribes coming to this region, there is little doubt that the critical mass which brought about this linguistic shift was provided by the same Oguz-Turkmen tribes that had come to Anatolia. The Azeris of today are an overwhelmingly sedentary, detribalized people. Anthropologically, they are little distinguished from the Iranian neighbors.”

John Perry:

“We should distinguish two complementary ways in which the advent of the Turks affected the language map of Iran. First, since the Turkish-speaking rulers of most Iranian polities from the Ghaznavids and Seljuks onward were already iranized and patronized Persian literature in their domains, the expansion of Turk-ruled empires served to expand the territorial domain of written Persian into the conquered areas, notably Anatolia and Central and South Asia. Secondly, the influx of massive Turkish-speaking populations (culminating with the rank and file of the Mongol armies) and their settlement in large areas of Iran (particularly in Azerbaijan and the northwest), progressively turkicized local speakers of Persian, Kurdish and other Iranian languages” (John Perry. "The Historical Role of Turkish in Relation to Persian of Iran". Iran & the Caucasus, Vol. 5, (2001), pp. 193-200.)

According to C.E. Bosworth:

“The eastern Caucasus came under Saljuq control in the middle years of the 5th/11th century, and in ca. 468/1075-56 Sultan Alp Arslān sent his slave commander ʿEmād-al-dīn Savtigin as governor of Azerbaijan and Arrān, displacing the last Shaddadids. From this period begins the increasing Turkicization of Arrān, under the Saljuqs and then under the line of Eldigüzid or Ildeñizid Atabegs, who had to defend eastern Transcaucasia against the attacks of the resurgent Georgian kings. The influx of Oghuz and other Türkmens was accentuated by the Mongol invasions. Bardaʿa had never revived fully after the Rūs sacking, and is little mentioned in the sources.” (C.E. Bsowrth, Arran in Encyclopedia Iranica)

According to Fridrik Thordarson:

“Iranian influence on Caucasian languages. There is general agreement that Iranian languages predominated in Azerbaijan from the 1st millennium b.c. until the advent of the Turks in a.d. the 11th century (see Menges, pp. 41-42; Camb. Hist. Iran IV, pp. 226-28, and VI, pp. 950-52). The process of Turkicization was essentially complete by the beginning of the 16th century, and today Iranian languages are spoken in only a few scattered settlements in the area.”